1. Field of the Invention
The present invention relates to a heating device for heating air and to a method for mounting the same. Further, the invention relates to radiator subassemblies and positioning frames that form a part of the heating device. In particular, the present invention relates to heating devices that comprise PTC elements.
2. Description of the Related Art
In automotive vehicles, in particular those having economically operating optimized internal combustion engines, heating devices or radiators are used for heating the passenger compartment and the engine. Heating devices, however, are also suitable for other purposes in a wide area of applications, e.g. in the field of building installations (room air conditioning), industrial plants, or the like.
Presently, several techniques have been developed in the field. In EP 0 575 649 B1 by Bohlender et al. a radiator is disclosed which contains heating elements that are assembled to form prefabricated units consisting of sheet bands which are riveted to each other and which enclose a lamella band. The PTC elements used are held in windows or openings of plastic frames. For mounting purposes the prefabricated heating element units and the plastic frames provided with PTC elements are stacked and fixed by means of a holding frame. Such a type of construction has the significant drawback that the assembly of such a radiator is troublesome.
DE 197 06 199 A1 describes an electric heating unit in which heating elements are stacked that carry PTC elements and comprise corrugation ribs. To secure the position of the corrugation ribs between the heating elements, projections are used on the sheets that enclose the PTC elements. Such technique does again not lead to an easy assembly of the heating unit in its entirety because the heating elements and the corrugation ribs must still be stacked subsequently and individually.
EP 0 379 873 A2 by Starck describes a device for heating gases using PTC elements that are fixed in a frame part which is disposed inside of a U-shaped profile member and which is covered by a cover plate. For enabling heat transfer to the surrounding air the arrangement has lamellae thereon fixed in a non-positive manner that are provided with an opening for this purpose. Although heating units are thereby created which have clampingly seated thereon heat discharge lamellae, such a device can only be mounted under great efforts because the lamellae must be slid thereonto individually. Moreover, the arrangement is not very stable, nor can it be stacked easily.
The present invention therefore has been made in consideration of the above situation, and has as its primary object to provide a heating device, a radiator subassembly and a positioning frame with improved mounting characteristics as well as a method for mounting such a heating device.
It is another object of the present invention to reduce the weight of the device and the production costs.
Another object of the present invention is to improve the technique of electrically connecting the heat elements to the power supply.
It is still another object of the present invention to allow for mounting radiator elements of a great length as well as heating elements having a great heat output.
Another object of the present invention is to increase mechanical and thermal stability of the overall arrangement.
To achieve these objects, according to a first aspect of the present invention, there is provided a heating device for heating air, wherein the heating device comprises at least one radiator element and at least one positioning frame. Said at least one positioning frame is arranged for being fixed to said at least one radiator element. Said at least one positioning frame comprises means for receiving at least one PTC (Positive Temperature Coefficient) element. Said at least one positioning frame further comprises means for clipping a radiator element to at least one side of the positioning frame.
According to a second aspect, the invention provides a method for assembling a heating device, wherein the method comprises the steps of connecting radiator sheets to lamella elements for prefabricating radiator elements; clipping the prefabricated radiator elements and/or electrode sheets to positioning frames and inserting PTC elements for prefabricating radiator subassemblies; stacking the prefabricated radiator subassemblies; and enclosing the stacked radiator subassemblies in a holding frame.
According to a third aspect of the present invention, there is provided a positioning frame comprising means for receiving at least one PTC (Positive Temperature Coefficient) element; and means for clipping a radiator element to at least one side of the positioning frame.
According to a fourth aspect, the invention provides a radiator subassembly comprising a radiator element and a positioning frame clipped to the radiator element. The positioning frame comprises means for receiving at least one PTC (Positive Temperature Coefficient) element.